199 research outputs found
Calogero-Sutherland Approach to Defect Blocks
Extended objects such as line or surface operators, interfaces or boundaries
play an important role in conformal field theory. Here we propose a systematic
approach to the relevant conformal blocks which are argued to coincide with the
wave functions of an integrable multi-particle Calogero-Sutherland problem.
This generalizes a recent observation in 1602.01858 and makes extensive
mathematical results from the modern theory of multi-variable hypergeometric
functions available for studies of conformal defects. Applications range from
several new relations with scalar four-point blocks to a Euclidean inversion
formula for defect correlators.Comment: v2: changes for clarit
Torus invariant divisors
Using the language of polyhedral divisors and divisorial fans we describe
invariant divisors on normal varieties X which admit an effective codimension
one torus action. In this picture X is given by a divisorial fan on a smooth
projective curve Y. Cartier divisors on X can be described by piecewise affine
functions h on the divisorial fan S whereas Weil divisors correspond to certain
zero and one dimensional faces of it. Furthermore we provide descriptions of
the divisor class group and the canonical divisor. Global sections of line
bundles O(D_h) will be determined by a subset of a weight polytope associated
to h, and global sections of specific line bundles on the underlying curve Y.Comment: 16 pages; 5 pictures; small changes in the layout, further typos
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Recycling CO2from flue gas for CaCO3nanoparticles production as cement filler: A Life Cycle Assessment
CaCO3 nanoparticles as filler have received considerable attention for the mechanical improvement that they
provide to cements. However, their life-cycle impact on the environment remains almost unexplored, even if the
cement industry is considered one of the largest CO2 emitters. In this perspective, this research work assessed a
novel method for using CO2 from cement flue gases to produce nanoCaCO3 as cement filler within the cradle to
cradle thinking. For this purpose, two routes of CO2 capture were assessed followed by the study of the synthesis
of CaCO3 through a mineral carbonation. Three scenarios for the synthesis of CaCO3 nanoparticles were assessed
targeting the use of waste or by-products as raw materials and recirculation of them to reduce any kind of
emission. The three scenarios were evaluated by means of the Life Cycle Assessment methodology. Once the best
considered route for nanoCaCO3 production was determined, this research work examined the environmental
effect of including 2 wt% of CaCO3 nanoparticles into the cement. Closing the loop follows a circular economy
approach since the CO2 is captured within the same cement factory. The results were compared with conventional
Portland cement. Regarding nanoCaCO3 results, the scenario with simultaneous production of NH4Cl, and
using as calcium source CaCl2 deriving from the soda ash Solvay process, proved to be the best option. Moreover,
when cement was filled with 2 wt% of this nanoCaCO3, the benefit in terms of emission reductions in the Climate
Change category was higher than 60 % compared to the conventional Portland cement.This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme under Grant Agreement No. 768583- RECODE project (Recycling carbon dioxide in the cement
industry to produce added-value additives: a step towards a CO2 circular
economy, https://www.recodeh2020.eu/). This paper reflects only the
author's view and the content is the sole responsibility of the authors.
The European Commission or its services cannot be held responsible for
any use that may be made of the information it contains.Publicad
Affine T-varieties of complexity one and locally nilpotent derivations
Let X=spec A be a normal affine variety over an algebraically closed field k
of characteristic 0 endowed with an effective action of a torus T of dimension
n. Let also D be a homogeneous locally nilpotent derivation on the normal
affine Z^n-graded domain A, so that D generates a k_+-action on X that is
normalized by the T-action. We provide a complete classification of pairs (X,D)
in two cases: for toric varieties (n=\dim X) and in the case where n=\dim X-1.
This generalizes previously known results for surfaces due to Flenner and
Zaidenberg. As an application we compute the homogeneous Makar-Limanov
invariant of such varieties. In particular we exhibit a family of non-rational
varieties with trivial Makar-Limanov invariant.Comment: 31 pages. Minor changes in the structure. Fixed some typo
The Complete One-Loop Dilation Operator of N=2 SuperConformal QCD
We evaluate the full planar one-loop dilation operator of N=2 SuperConformal
QCD, the SU(N_c) super Yang-Mills theory with N_f = 2 N_c fundamental
hypermultiplets, in the flavor-singlet sector. Remarkably, the spin-chain
Hamiltonian turns out to be completely fixed by superconformal symmetry, as in
N=4 SYM. We present a more general calculation, for the superconformal quiver
theory with SU(N_c)X SU(N_c) gauge group, which interpolates between N=2 SCQCD
and the Z_2 orbifold of N=4 SYM; here symmetry fixes the Hamiltonian up to a
single parameter, corresponding to the ratio of the two marginal gauge
couplings.Comment: v2: typo corrected, cosmetic changes. JHEP versio
Understanding the differential hygienic behavior towards drone brood in Apis mellifera colonies from Argentina
Brood diseases of Apis mellifera colonies constitute a main problem of beekeeping worldwide. Worker bees display a social health mechanism that consists in detecting, uncapping and removing dead or diseased brood from the hive: the hygienic behavior (CH). These activities are induced by olfactory cues and have been described as associated to hygiene of brood parasitized by Varroa destructor. This mite have preference for drone brood, but the efficiency of CH towards their cells is significantly lower compared with cells of worker brood, being left uninspected by workers. Some authors suggest that a possible cause of the CH differences is due to the cell wax cap of drone brood (thicker than worker cells) acting as a barrier to volatile compounds and obstructing disease detection. The aims of this research were to study the differential CH towards worker and drone brood belonging to highly hygienic colonies from Argentina, and to explore the importance of drone cell wax cap as an interfering factor in the transmission of chemical signals. To this end, removal percentages of pin-killed worker and drone brood were recorded and an innovative cell wax cap exchange was implemented in three different treatments: pin-killed worker pupa with a healthy drone cell wax cap; a healthy worker pupa with a pin-killed drone cell wax cap; and a healthy worker pupa covered with a healthy drone cell wax cap (control). Results showed a greater removal towards worker cells than drone cells. For the cell wax cap exchange experiment, we found that the removal of pin-killed worker pupae covered with healthy drone cell wax cap was significantly high, while the removal of healthy worker pupae covered with pin-killed drone opercula was low. These preliminary results confirms a differential behavior between both type of brood cells and suggests that the cell wax cap of drone brood is not interfering the detection of chemical compounds from the diseased brood by worker bees, regardless the thickness. This work contributes to a better understanding of the detection activity of different types of diseased brood and provides information useful to control strategies of varroosis and other brood diseases.Fil: Dowd, D. Duggan. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Muntaabski, Irina. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Russo, R. M.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Landi, L.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación de Recursos Naturales. Instituto de Recursos Biológicos; ArgentinaFil: Lanzavecchia, S. B.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Cladera, J. L.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; ArgentinaFil: Palacio, M. A.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: Bedascarrabure, E.. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion de Agroindustria. Instituto de Ingeniería Rural.; ArgentinaFil: Scannapieco, Alejandra Carla. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; ArgentinaFil: Liendo, María Clara. Instituto Nacional de Tecnologia Agropecuaria. Centro de Investigacion En Ciencias Veterinarias y Agronomicas. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo | Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Pque. Centenario. Instituto de Agrobiotecnologia y Biologia Molecular. Grupo Vinculado Instituto de Genetica "ewald A. Favret" Al Iabimo.; Argentina46th Apimondia International Apicultural Congress: Beekeeping together within agricultureQuébecCanadáInternational Federation of Beekeepers' AssociationsCanadian Honey Counci
La formación docente en venezuela en el contexto de la consulta nacional por la calidad educativa: apuntes preliminares para el desarrollo de las políticas de formación docente.
Este artículo constituye un acercamiento al contexto educativo en el cual se produce el debate nacional sobre la Consulta Nacional por la Calidad Educativa en su fase culminante, a través de una mirada a la formación inicial de docentes para el subsistema de Educación Básica. Esta convocatoria realizada por el Ejecutivo del país por intermedio del Ministerio del Poder Popular para la Educación (MPPE) ocurre en un complejo clima político y social del país, sometido desde hace más de una década a las presiones políticas y económicas de fuerzas internas apuntaladas por el poder político y económico transnacional que amenazan seriamente la pervivencia del proceso revolucionario Bolivariano, y cuyo único propósito es revertir las conquistas políticas y sociales logradas en este tiempo de cambios en todos los órdenes. De allí que, a los efectos del presente escrito, se hará particular énfasis en el tema de la formación inicial de los docentes, en particular desde la mirada de la evolución de este proceso, reconocido actualmente como uno de los problemas recurrentes que, pese a diferentes iniciativas orientadas hacia el diseño de una política en esta dirección, sigue siendo una de las materias pendientes del actual proceso político venezolano
From Scattering Amplitudes to the Dilatation Generator in N=4 SYM
The complete spin chain representation of the planar N=4 SYM dilatation
generator has long been known at one loop, where it involves leading
nearest-neighbor 2 -> 2 interactions. In this work we use superconformal
symmetry to derive the unique solution for the leading L -> 2 interactions of
the planar dilatation generator for arbitrarily large L. We then propose that
these interactions are given by the scattering operator that has N=4 SYM
tree-level scattering amplitudes as matrix elements. We provide compelling
evidence for this proposal, including explicit checks for L=2,3 and a proof of
consistency with superconformal symmetry.Comment: 39 pages, v2: reference added and minor changes, published versio
Chromatin condensation and recruitment of PHD finger proteins to histone H3K4me3 are mutually exclusive
Histone post-translational modifications, and specific combinations they create, mediate a wide range of nuclear events. However, the mechanistic bases for recognition of these combinations have not been elucidated. Here, we characterize crosstalk between H3T3 and H3T6 phosphorylation, occurring in mitosis, and H3K4me3, a mark associated with active transcription. We detail the molecular mechanisms by which H3T3ph/K4me3/T6ph switches mediate activities of H3K4me3-binding proteins, including those containing plant homeodomain (PHD) and double Tudor reader domains. Our results derived from nuclear magnetic resonance chemical shift perturbation analysis, orthogonal binding assays and cell fluorescence microscopy studies reveal a strong anti-correlation between histone H3T3/T6 phosphorylation and retention of PHD finger proteins in chromatin during mitosis. Together, our findings uncover the mechanistic rules of chromatin engagement for H3K4me3-specific readers during cell division
Argyres-Douglas theories, the Macdonald index, and an RG inequality
We conjecture closed-form expressions for the Macdonald limits of the super-conformal indices of the (A1, A2n − 3) and (A1, D2n) Argyres-Douglas (AD) theories in terms of certain simple deformations of Macdonald polynomials. As checks of our conjectures, we demonstrate compatibility with two S-dualities, we show symmetry enhancement for special values of n, and we argue that our expressions encode a non-trivial set of renormalization group flows. Moreover, we demonstrate that, for certain values of n, our conjectures imply simple operator relations involving composites built out of the SU(2)R currents and flavor symmetry moment maps, and we find a consistent picture in which these relations give rise to certain null states in the corresponding chiral algebras. In addition, we show that the Hall-Littlewood limits of our indices are equivalent to the corresponding Higgs branch Hilbert series. We explain this fact by considering the S1 reductions of our theories and showing that the equivalence follows from an inequality on monopole quantum numbers whose coefficients are fixed by data of the four-dimensional parent theories. Finally, we comment on the implications of our work for more general (Formula presented.) superconformal field theories
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